


Let's Get this Party Started

by firesign10



Category: Supernatural
Genre: Brother-Sister Relationships, Car Sex, F/M, Fake/Pretend Relationship, Genderswap, High School Student Sam Winchester, Public Sex, Sexy Dancing, Sibling Incest, girl!Dean
Language: English
Status: Completed
Published: 2018-09-30
Updated: 2018-09-30
Packaged: 2019-07-20 20:35:14
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,539
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/16145012
Author URL: https://archiveofourown.org/users/firesign10/pseuds/firesign10
Summary: 16-year-old Sam gets invited to his first party and is totally awkward and feels uncool. Girl!Dean shows up and pretends to be his cool, older girlfriend in college and lets him feel her up in front of his envious peers.





	Let's Get this Party Started

**Author's Note:**

> One of my fills for 2018 Masquerade.

Sam wound his way through the crowded kitchen into the equally crowded living room, clutching his red plastic cup of cheap keg beer. It tasted sour, but he grimly sipped it anyway, hoping to catch a little buzz that would make this house party somewhat enjoyable. Right now, it felt like Purgatory, only full of horny guys trying to grope the flirty girls who were pretending to be more drunk than they really were.

He found an empty wooden chair in the corner of the room, gratefully sinking down on it so he could hide behind the mass of dancing teens. He should have known better than to come to this, but he hadn't been able to help the surge of hope that he'd meet someone, make some friends, before they moved on again. 

“Fortune favors the brave,” he muttered to himself. He'd said this to himself while combing his hair in the mirror at the motel, and his older sister Deana had laughed.

“What a crock,” she'd scoffed. “You don't have to be brave, Sammy. You just have to grab what you want.” She'd batted her eyes and run a hand over her perky breasts. “Or make it want to grab you.”

“Well, I'm not a slut, and I don't have big boobs to flash at everyone,” Sam had retorted. “So I guess I'm out of luck.”

Dee had come over and rubbed his shoulders, sliding a hand down over his fly. “Dude, if anyone knew what you were packing here, you'd have a line around the block.” She'd given him a squeeze, chuckling when his dick had jumped under her caress.

He'd shrugged her off anyway. “If anyone knew I fooled around with my sister, we'd be kicked out of school. Let me just go try and find a real girlfriend, okay?” He hadn't missed the hurt look that flashed over her face, but then she'd smiled cheerfully and waved him out the door.

And now he was here, alone and drinking piss-beer, and he was still hard from her caress. Great.

Annabeth from his chem class walked by, and he said hi and smiled at her. She looked at him blankly. “Do I know you?”

“Uh, yeah, I sit the next desk over in Horton's chem class, fifth period.” He tried to smile confidently even as his guts churned in embarrassment.

“Oh, uh, yeah! Nice to see you.” And she was gone, pulled away by some guy who was as tall as Sam, but had about sixty pounds more muscle. 

He sighed, sipped his crappy beer. Maybe it was time to go.

“What's a girl gotta do to get a beer around here?”

Sam's head whipped around. The people by the door fell back a little, and he was able to see the owner of that strong, clear voice. Not that he couldn't already tell.

Deana stood in the doorway, feet planted wide, hands on her hips. She wore one of Sam's plaid flannel shirts, but it was unbuttoned to below her boobs and tied in a knot above her belly button. Between the cleavage and the way she was bouncing, it was clear she wasn't wearing a bra. Distressed jeans clung to her hips and molded to her ass, ending above her ankles so that the leopard spike heels were well-displayed. Her light brown hair was piled loosely on her head, and the shiny deep rose lipstick make her full lips look even plumper.

She sashayed into the room, her sweet bubble-butt swaying while her heels tapped, and Sam could just about hear the tongues hitting the floor. All around the room girls were being abandoned as the guys zeroed in on this vision of walking slutty sex.

Heck, she was his sister, and his cock was ready to pound nails.

The music resumed, but most of the dancers were still fixated on Dee. She slowly cruised the room, a beer appearing in her hand at some point. She tousled hair here, ran a hand down a cheek there, gave a few considering looks. She came around the back of the room, leaving a wake of disappointment and blue balls behind her, stopping at Sam.

He looked up at her, wondering what her game was.

“Sam! I didn't know you'd be here! I just got home from college for the weekend,” she purred. “It's been a little while--stand up and let a girl take a gander at you.”

Setting his cup on the floor, Sam stood, looking down at her as he rose to his full height.

“You've grown, and you got even cuter.” She sidled into him, pressing her body against his. “How about a slow dance for your old girlfriend?”

Taking his hand, she tugged him into the middle of the room. The Eurythmics' Sweet Dreams began playing, and Dee wrapped her arms around Sam's neck. “What are you doing,” he hissed quietly as they danced, his hands resting lightly on her waist.

“Just go with it,” she whispered back, and planted a kiss on his lips. Her lipstick felt sticky, but underneath it he could feel the warmth of her mouth.

They danced a few moments, most of the room still watching them. A few couples joined them, swaying together while still looking at Sam and Dee.

Dee turned around inside Sam's hands, her ass rubbing against his crotch and making him grimace with his hard-on. “Dee, stop,” he muttered, trying to move his hips away, but she reached around and grabbed one of his cheeks, pulling him in close and keeping him there.

Already struggling with her extreme proximity, Sam was totally unprepared for Dee's other hand grabbing his and planting it squarely on her tit. “Oh yeah, baby, squeeze me!” she moaned loudly. Sam gritted his teeth, but his attempt at nonchalance was undercut by the unfettered sway of her breast as they moved. He could distinctly feel the mound of her nipple under the thread-bare flannel, and his fingertips caressed that bump again and again, rubbing and scratching it despite himself.

She moaned again, butt grinding on his fly. It looked like everyone was staring again, but Dee ignored them, tilting her head back to rest on Sam's collarbone, thrusting her chest out. A twitch of fabric, and suddenly his hand was resting on her bare boob, her smooth skin scorching. Her stiff nipple slid between his fingers and reflexively he pinched it, making her gasp. He could hear a murmur from the crowd, but he was completely wrapped up in Dee now; her soft perfume, the curve of her ass, the weight of her tit in his hand and the stab of her nip on his palm.

With a yank of her hands, Dee ripped her shirt open, proudly displaying her perfect breasts, round and heavy. She wound one arm around Sam's neck while cupping and squeezing herself, her fingers flicking and toying with her nipples. Sam heard a lot of heavy breathing and panting from the party-goers, and when he quickly scanned the room he could see several hands shoved into pants and up under skirts. His own dick was howling for attention, soaking wet spots into his boxers with spurts of pre-come.

“Come on, baby—fuck me!” Dee cried, and hooking a hand in Sam's waistband, she pranced out of the room, leading him along. Exiting the house, Sam saw the Impala parked right in front of the front steps. Dee flung the front passenger door open and pushed Sam in. “Get those jeans down!” she ordered. 

Sam did so, hurriedly pushing jeans and soggy boxes down to mid-thigh. Dee stripped her own jeans and panties off, leaving them on the grass. She jumped into the car and put her hands on the dash, facing out of the windshield. “Come on, baby! Fuck me right the fuck now!”

Sam grabbed her hip with one hand and guided himself in with the other. She was soaked, her tissues slick and hot, and he groaned with pleasure as she sank down on him. She rode him hard, rising and dropping, swiveling her hips, with lots of moans and arching her chest, practically pressing her boobs against the windshield. Sam didn't have to look around her to know everyone at the part was on those steps or in the front windows watching. When Dee decided to put on a show, she made it a good one.

With a stuttering of his hips, Sam came inside Dee, moaning as his cock pulsed. “Oh yeah, Sammy, that's it,” she crooned, then reached between her legs and finished herself off with deft fingers. She pulled off to drop onto the seat next to him, accepting some leftover paper napkins to clean up with.

“You're crazy,” he said, kissing her. 

“Yeah, but you'll be Mr. Popular now,” she said. “Plus we got to fuck in front of everyone. I call that a win-win.”

They laughed together. “Let's go home. Dad's away, we can do it again, take our time a little more.” She reached out of the car and grabbed her clothes to the hoots of the crowd. “Hit it, Sammy!”

With an approving growl from the Impala, the Winchesters headed off.


End file.
